Typical self-propelled pothole patching vehicles are provided with a cab and a chassis adapted to carry an asphalt storage hopper, a conveyor for transporting the asphalt front the hopper to the roadway and a tamping means for compacting the asphalt into the pothole, either of the roller type or a flat tamping plate provided with a vibrator.
Some pothole patching vehicles have a front asphalt delivery system for delivering asphalt to the pothole within the field of view of the operator. Some of these conveyor systems are adapted to be longitudinally extendible and retractible along the vehicle axis in addition to swivelling or pivoting laterally. However, since the hopper-to-conveyor connection must be maintained for continuous delivery of asphalt during the patching process, in some vehicles the conveyor is coupled to the hopper in such a way that both the conveyor and hopper move together in tandem during extendible and retractible motion thereof.
This arrangement is not entirely satisfactory since coupling the hopper and conveyor in this way limits the longitudinal range accessible to the conveyor, depending on the chassis design. As a result, having to continuously move the vehicle between potholes tends to slow down the pothole patching process.
It is customary to provide pothole patching vehicles with various accessories for preparing the pothole prior to filling, some examples being flame torches for drying the pothole, compressed air for blowing loose debris out of the pothole and tack oil spraying means for coating the pothole prior to filling in order to increase the bonding between the new and old asphalt.
It has been found that direct flame heating of the asphalt on the pothole interior can damage the asphalt thereby degrading its ability to bond to the new asphalt. It has also been found that when tamping the asphalt after the pothole has been filled, asphalt tends to stick to the tamping plate, which prevents a smooth and continuous road surface from being achieved. Also, the asphalt must be continuously cleaned off the tamping plate, otherwise, once it dries and hardens, it becomes very difficult to clean off.